1. Field of the Invention
The invention relates to a directly-visible transmissive type or projector type of liquid crystal display device.
2. Description of Related Art
A directly-visible transmissive type or projector type of liquid crystal display device is provided with a halogen lamp or the like as a light source. A lamp of this type is inferior from the utilization efficiency point of view, in that it generates a large amount of heat and it also emits a great deal of light outside the visible range. This utilization efficiency is degraded even further if the light is passed through a color filter to form a color display.
An image display device that uses laser beams of three colors (red, green, and blue) as a light source is disclosed in Japanese Patent Laying-Open No. 4-263244. Since a laser beam is colored light of a specific wavelength, the utilization efficiency is higher than that of a prior-art lamp.
However, the efficiency with which the light is utilized is also affected by the aperture ratio of the liquid crystal panel. In other words, not all of the light from the light source passes through the liquid crystal panel; some of it is blocked by dead areas such as the black matrix, signal lines, and transistors. To improve the ratio of light that passes through, it is necessary to reduce the size of dead areas, or increase the aperture ratio. However, since it is impossible to remove such dead areas, there is a limit to improvements in aperture ratio.